Benzene and naphthylene derivatives and their use as UV screening agents

ABSTRACT

Methods for making UV screening compositions by combining benzoxazolyl benzene derivatives of formula (I): 
                         
wherein R 1  is hydrogen, C 1-20 -alkyl or C 2-20 -alkenyl; R 2  and R 3  are independently a group —C(R 4 ,R 5 )C(R 6 )═C(R 7 ,R 8 ) (a) or a group —C(R 4′ ,R 5′ )CH(R 6′ )CH(R 7′ ,R 8′ ) (b), wherein R 4 , R 5 , R 6 , R 7 , R 8 , R 4′ , R 5′ , R 6′ , R 7′  and R 8′  are independently, hydrogen, C 1-10 -alkyl or C 2-10 -alkenyl, or C 2-10 -alkyl or C 3-10 -alkenyl containing at least one oxygen atom interrupting the hydrocarbon chain; or wherein R 4 , R 5 , R 6 , R 4′ , R 5′  and R 6′  are hydrogen, C 1-10 -alkyl or C 2-10 -alkyl containing at least one oxygen atom interrupting the hydrocarbon chain, or alkyl substituted by silane or oligosiloxane moiety, and one of R 7  and R 8  or R 7′  and R 8′  is a silane or oligosiloxane moiety and the other one of R 7  and R 8  or R 7′  and R 8′  is hydrogen; and X is phenylene or naphthylene, or substituted phenylene or naphthylene with a cosmetic base. Methods of protecting a surface from UV radiation by applying a UV screening agent of formula I to a surface such as hair or skin.

This application is a Divisional of prior application Ser. No.10/467,430 filed Aug. 4, 2003, which is the U.S. National Stage ofInternational Application No.: PCT/EP02/00847 filed Jan. 28, 2002, nowU.S. Pat. No. 7,019,020 issued Mar. 28, 2006.

The present invention relates to novel benzoxazolyl benzene derivatives.

More particularly, the invention relates to benzoxazolyl benzenederivatives of the general formula I

wherein

-   R¹ is hydrogen, C₁₋₂₀-alkyl or C₂₋₂₀-alkenyl;-   R² and R³ are independently a group —C(R⁴,R⁵)C(R⁶)═C(R⁷,R⁸) (a) or a    group —C(R^(4′),R^(5′))CH(R^(6′))CH(R^(7′),R^(8′)) (b), wherein R⁴,    R⁵, R⁶, R⁷, R⁸, R^(4′),R^(5′), R^(6′), R^(7′) and R^(8′) are,    independently, hydrogen, C₁₋₁₀-alkyl or C₂₋₁₀-alkenyl, or    C₂₋₁₀-alkyl or C₃₋₁₀-alkenyl containing at least one oxygen atom    interrupting the hydrocarbon chain; or wherein R⁴, R⁵, R⁶, R^(4′),    R^(5′) and R^(6′) are hydrogen, C₁₋₁₀-alkyl or C₂₋₁₀-alkyl    containing at least one oxygen atom interrupting the hydrocarbon    chain, or alkyl substituted by a silane or oligosiloxane moiety, and    one of R⁷ and R⁸ or R^(7′) and R^(8′) is a silane or oligosiloxane    moiety and the other one of R⁷ and R⁸ or R^(7′) and R^(8′) is    hydrogen; and-   X is phenylene or naphthylene, or substituted phenylene or    naphthylene.

In another aspect, the present invention relates to novel UV screeningcompositions, particularly topical compositions for cosmetic ordermatological use; and to the use of compounds of formula I as definedabove as UV screening agents, particularly for protecting human skin orhair against UV radiation.

As used herein, C₁–C₂₀-alkyl and C₁–C₁₀-alkyl denote straight chain orbranched saturated hydrocarbon residues with 1 to 20 (or 1 to 10) carbonatoms, such as methyl, ethyl, propyl, isopropyl, thexyl, (1,1,2dimethylpropyl), n-butyl, sec. butyl, tert. butyl, pentyl, neopentyl,hexyl, 2-ethyl-hexyl, octyl and the like.

C₂–C₂₀-alkenyl and C₂–C₁₀-alkenyl denote straight chain or branchedhydrocarbon residues with 2 to 20 (or 2–10) carbon atoms and containingat least one C—C double bond, such as vinyl, allyl, 2-butenyl,methallyl, 2-penten-3-yl, 3-hexen-2-yl, 3-hepten-2-yl, 3-octen-2-yl,1-octen-3-yl and 2-octen-1-yl.

The term “C₂–C₁₀-alkyl containing at least one oxygen atom interruptingthe hydrocarbon chain” denotes straight chain or branched saturatedhydrocarbon residues with 2 to 10 carbon atoms which are bound via acarbon atom and have at least one —CH₂O— group, such as methoxymethyl,4-oxa-hexyl, 4,7-dioxa-nonyl and 4,7,10-trioxa-dodecyl. Similarly, theterm “C₃–C₁₀-alkenyl containing at least one oxygen atom interruptingthe hydrocarbon chain” denotes straight chain or branched olefinicallyunsaturated hydrocarbon residues with 3 to 10 carbon atoms which arebound via a carbon atom and have at least one —CH₂O— group and at leastone C—C double bond.

A silane moiety is, e.g., a group —SiR^(a)R^(b)R^(c), wherein R^(a),R^(b) and R^(c) each independently are C₁–C₆alkyl or phenyl. Preferredsilane moieties are trimethylsilane, triethylsilane, tripropylsilane,triisopropylsilane, dimethyl tert.butylsilane, dimethyl thexylsilane,triphenylsilane, dimethylphenylsilane and the like.

An oligosiloxane moiety is, e.g., a group of the general formula IVa,IVb or IVc—SiR^(a) _(m)(OSiR^(b) ₃)_(n)  (IVa)

wherein m=0, 1 or 2; n=1, 2 or 3 and m+n=3, R^(a) and R^(b) are C₁–C₆alkyl or phenyl, preferably C₁–C₄ alkyl, more preferably methyl, and ris an integer from 1 to 9, preferably 1 to 3. Preferred oligosiloxanemoieties are —SiMe₂(OSiMe₃) and —SiMe (OSiMe₃)₂ wherein Me is methyl.

If X is substituted phenylene or naphthylene, the substituents may be 1or 2 hydroxly or C₁₋₂₀alkoxy groups. Preferably, X is unsubstitutedp-phenylene or 1,4-naphthylene, and, most preferably, p-phenylene.

The compounds of formula I preferably contain a lipophilic or asterically hindered substituent R¹, R² or R³. Examples of lipophilicsubstituents are silane or oligosiloxane moieties, and alkyl or alkenylgroups having 5 or more, preferably 8 or more carbon atoms, such as2-ethyl-hexyl, decyl, dodecyl, 3-octen-2-yl, 1-octen-3-yl, and2-octenyl. A sterically hindered substituent suitably is an alkyl grouphaving a tertiary carbon atom, such as isopropyl, or quaternary carbonatom, such as tert.-butyl, tert.-amyl (2-methyl-2-pentyl), and2,4-trimethyl-2-pentyl.

Preferred compounds of the formula I above are those wherein R² and R³are a group (a) as defined above wherein R⁵, R⁶ and R⁷ are hydrogen andR⁴ and R⁸ are C₁–C₁₀-alkyl, particularly those wherein R⁴ is methyl andR⁸ is C₃–C₅-alkyl; or wherein R⁵, R⁶, R⁷ and R⁸ are hydrogen and R⁴ isC₁–C₁₀-alkyl, particularly C₃–C₅-alkyl. Further, compounds of formula Iwherein R² and R³ are a group (b) as defined above wherein R^(5′),R^(6′), R^(7′) are hydrogen and R^(4′) and R^(8′) are C₁–C₁₀-alkyl,particularly when R^(4′) is methyl and R^(8′) is C₃–C₅-alkyl arepreferred. Finally, compounds of formula I wherein R² and R³ are a group(b) as defined above wherein R^(5′), R^(6′), R^(7′) are hydrogen andR^(8′) is an oligosiloxane moiety, or wherein R^(4′), R^(5′) and R^(7′)are hydrogen, R^(6′) is C₁–C₁₀-alkyl and R^(8′) is an oligosiloxanemoiety and compositions containing such compounds are preferred.

The compounds of the general formula I can be prepared by alkylating acompound of the general formula II

wherein X and R² are as defined above, with a compound of the generalformula Y—R²¹,wherein Y is a leaving group and R²¹ is —C(R⁴,R⁵)C(R⁶)═C(R⁷,R⁸), whereinR⁴, R⁵, R⁶, R⁷ and R⁸ are, independently, hydrogen, C₁₋₁₀-alkyl orC₂₋₁₀-alkenyl, or C₂₋₁₀-alkyl or C₃₋₁₀-alkenyl containing at least oneoxygen atom interrupting the hydrocarbon chain; to yield a compound ofthe general formula III

wherein X, R¹ and R²¹ are as defined above, heating the compound of thegeneral formula III to yield a compound of the general formula I whereinX and R¹ are as defined above and R² and R³ are a group R²¹ as definedabove, and, if desired, either reacting the so-obtained compound of thegeneral formula I with a silane or oligosiloxane carrying a free SiHgroup to obtain a compound of the general formula I wherein R² and R³are a group —C(R⁴,R⁵)CH(R⁶)C(R⁷,R⁸), wherein one of R⁷ and R⁸ ishydrogen and the other one of R⁷ and R⁸ is a silane or oligosiloxanemoiety, and R⁴, R⁵ and R⁶ are hydrogen, C₁–C₁₀-alkyl or C₂–C₁₀-alkylcontaining at least one oxygen atom interrupting the hydrocarbon chain,or C₁–C₁₀-alkyl substituted by a silane or oligosiloxane moiety; orhydrogenating the so-obtained compound of formula I to obtain a compoundof the general formula I wherein R² and R³ are —C(R⁴,R⁵)CH(R⁶)C(R⁷,R⁸),wherein R⁴, R⁵, R⁶, R⁷ and R⁸ are hydrogen or C₁–C₁₀-alkyl orC₂–C₁₀-alkyl containing at least one oxygen atom interrupting thehydrocarbon chain.

In the first reaction step the compound of formula II is reacted with acompound of formula Y—R²¹. The leaving group Y may be any conventionalleaving group such as halogen, e.g., chloro, bromo, or a sulfonyloxygroup, e.g., tosyloxy or mesyloxy. The reaction can be carried out in amanner known per se for the alkylation of phenolic hydroxy groups, i.e.,in the presence of a base such as an alkali carbonate, e.g., sodiumcarbonate, alkali hydroxide or alkali alcoholates, e.g., sodiummethylate; an amine such as triethyl amine, N,N-dimethylamino pyridineor 1,4-diazabicyclo[2.2.2]octane (DABCO); in a polar solvent e.g., analcohol such as n-butanol, an ether such as diethyleneglycol mono-methylether, tetrahydrofuran or dioxan; or in dimethyl formamide, dimethylsulfoxide, N,N-dimethyl propylene urea or 1-methylpyrrolidone, or in asolvent which simultaneously may serve as a base, such asN,N-dimethylamino pyridine, at temperatures from room temperature up tothe boiling point of the reaction mixture. The phenol ether of theformula III obtained can be rearranged by heating, suitably to atemperature of from 50 to 300° C., if desired, in a solvent, suitably ina solvent that is conventionally used in Claisen rearrangements, e.g.,in diethyl aniline or trichloro benzene. In the same reaction step, ringclosure to form the oxazole ring takes place, thus yielding a compoundof formula I wherein X and R¹ are as defined above, and R² and R³ are agroup (a) as defined above.

The Claisen rearrangement may result in the formation of isomers withrespect to the structure and bonding site of the groups R² and R³. Whilethese isomers may be separated by conventional methods such aschromatography it is preferred to use such mixture of isomers in thecompositions of the present invention if they are obtained in theClaisen rearrangement.

If desired, a compound of the formula I wherein R² and R³ are a group(a) can be hydrosilylated by reaction with a silane, oligosiloxane orpolysiloxane carrying a free SiH group. The hydrosilation reaction issuitably carried out in the presence of a transition metal catalyst e.g.a platinum catalyst such as platinum on charcoal, or a platinum complexcatalyst such as e.g. divinyl-tetramethyl disiloxane platinum, ammoniumhexachloroplatinate (IV), hydrogen hexachloroplatinate (IV) hydrate, ora Rhodium catalyst, e.g. Rh₂Cl₂(cyclooctadiene)₂ in a suitable reactionsolvent such as e.g. in toluene. The reactants are usually present inabout equal molar amounts and the reaction is carried out at a somewhatelevated temperature, e.g. at about 60° C.–150° C., preferably at about40° C.–100° C., more preferably at about 80° C.

Alternatively, an alkenyl group in a compound of the formula I whereinR² and R³ are a group (a) can be hydrogenated. The hydrogenation can becarried out by methods known per se for the hydrogenation of olefinicdouble bonds, e.g. with elemental hydrogen in the presence of a noblemetal catalyst such as Pd, or with Raney-Ni, preferably with elementalhydrogen in the presence of an appropriate catalyst which does notattack the triazole ring, e.g., a partially inactivated noble metalcatalyst such as a Lindlar catalyst.

By the process of the present invention, the compounds of the generalformula I may be obtained as mixtures of isomers of the substituents R²and R³ depending on the conditions of the Claisen rearrangement of thecompounds of the formula III.

The starting compounds of formula II inasmuch as they are not known ordescribed hereinafter can be prepared in analogy to methods known per seor described hereinafter. Thus, terephthalic acid (ornaphthaline-1,4-dicarboxylic acid) or a reactive derivative thereof suchas an acid halogenide can be reacted with o-amino phenol which may besubstituted by a substituent as defined for R¹.

The compounds of the general formula I are photostable and have strongabsorption maxima in the UV-A region with ε values up to 58,000 and asteep downgrade of the absorption curve towards higher wave lenghts.Accordingly, they can be used as UV screening agents, especially inpreparations for skin protection and sunscreen preparations for everydaycosmetics, which may comprise a compound of formula I in a cosmetic basewhich is conventional for such preparations and which may contain otherconventional UV-A and/or UV-B filters. Said combinations of UV filterscan show a synergistic effect. The manufacture of said light screeningpreparations is well known to the skilled artisan in this field. Theamount of compounds of the general formula I and other known UV-filtersis not critical. Suitable amounts are about 0.5 to about 12% of asunscreen agent, i.e., a compound of formula I either alone or incombination with other UV filters. The compounds of the general formulaI exhibit good lipophilicity and thus can be incorporated well into oiland fat containing topical preparations. In the preparations a mixtureof compounds of formula I may be present.

Suitable UV B filters, i.e. substances having absorption maxima betweenabout 290 and 320 nm, for combination with the compounds of the formulaI are for example the following:

-   Acrylates such as 2-ethylhexyl 2-cyano-3,3-diphenylacrylate    (octocrylene, PARSOL 340), ethyl 2-cyano-3,3-diphenylacrylate and    the like;-   Camphor derivatives such as 4-methyl benzylidene camphor (PARSOL    5000), 3-benzylidene camphor, camphor benzalkonium methosulfate,    polyacrylamidomethyl benzylidene camphor, sulfo benzylidene camphor,    sulphomethyl benzylidene camphor, therephthalidene dicamphor    sulfonic acid and the like;-   Cinnamate derivatives such as octyl methoxycinnamate (PARSOL MCX),    ethoxyethyl methoxycinnamate, diethanolamine methoxycinnamate    (PARSOL Hydro), isoamyl methoxycinnamate and the like as well as    cinnamic acid derivatives bond to siloxanes;-   Organosiloxane compounds containing benzmalonate groups as described    in EP 358584 B1, EP 538,431 B1 and EP 709,080 A1;-   Pigments such as microparticulated TiO₂, and the like. The term    “microparticulated” refers to a particle size from about 5 nm to    about 200 nm, particularly from about 15 nm to about 100 nm. The    TiO₂ particles may also be coated by metal oxides such as e.g.    aluminum or zirconium oxides or by organic coatings such as e.g.    polyols, methicone, aluminum stearate, alkyl silane. Such coatings    are well known in the art.-   Imidazole derivatives such as e.g. 2-phenyl benzimidazole sulfonic    acid and its salts (PARSOL HS). Salts of 2-phenyl benzimidazole    sulfonic acid are e.g. alkali salts such as sodium- or potassium    salts, ammonium salts, morpholine salts, salts of primary, sec. and    tert. amines like monoethanolamine salts, diethanolamine salts and    the like.-   Salicylate derivatives such as isopropylbenzyl salicylate, benzyl    salicylate, butyl salicylate, octyl salicylate (NEO HELIOPAN OS),    isooctyl salicylate or homomenthyl salicylate (homosalate, HELIOPAN)    and the like;-   Triazone derivatives such as octyl triazone (UVINUL T-150), dioctyl    butamido triazone (UVASORB HEB) and the like.

Suitable UV A filters i.e. substances having absorption maxima betweenabout 320 and 400 nm, for combination with the compounds of the formulaI are for example the following:

-   Dibenzoylmethane derivatives such as    4-tert.butyl-4′-methoxydibenzoyl-methane (PARSOL 1789),    dimethoxydibenzoylmethane, isopropyldibenzoylmethane and the like;-   Benzotriazole derivatives such as    2,2′-methylene-bis-(6-(2H-benzotriazole-2-yl)-4-(1,1,3,3,-tetramethylbutyl)-phenol    (TINOSORB M) and the like;-   Pigments such as microparticulated ZnO and the like. The term    “microparticulated” refers to a particle size from about 5 nm to    about 200 nm, particularly from about 15 nm to about 100 nm. The ZnO    particles may also be coated by metal oxides such as e.g. aluminum    or zirconium oxides or by organic coatings such as e.g. polyols,    methicone, aluminum stearate, alkyl silane. Such coatings are well    known in the art.

As dibenzoylmethane derivatives are photolabile it is necessary tophotostabilize these UV-A screening agents. Thus, dibenzoylmethanederivatives such as e.g. PARSOL 1789 when used in combination with thecompounds of formula I can be stabilized by the following stabilizingagents:

3,3-diphenylacrylate derivatives as described in EP 514,491 B1 and EP780,119 A1;

benzylidene camphor derivatives as described in U.S. Pat. No. 5,605,680;

organosiloxanes containing benzmalonate groups as described in EP358,584 B1, EP 538,431 B1 and EP 709,080 A1.

Further, UV screening agents absorbing in the region overlapping UV-Aand UV-B such as those disclosed in EP 895,776 and EP 780,382 may beused as additional ingredients in the compositions of the presentinvention.

As cosmetic bases conventional for light screening compositions in thescope of the present invention there can be used any conventionalpreparation which corresponds to the cosmetic requirements, e.g. creams,lotions, emulsions, salves, gels, solutions, sprays, sticks and milks;see also Lowe and Shaath (eds.), Sunscreens, Development, Evaluation andRegulatory Aspects, Marcel Dekker, Inc. New York and Basel (1990).

The invention is illustrated further by the Examples which follow.

EXAMPLE 1 Preparation of1,4-bis-[2-(5-tert.-butyl-7-allyl-benzoxazol)-yl]-benzene

(a) Terephtalic acid chloride: To 40.9 g of terephtalic acid in 250 mlof toluene and 3.3 ml of pyridine, 41.1 ml of thionylchloride was slowlyadded at a temperature between 22 and 35° C. The reaction mixture washeated to 80° C. for four hours. From the cooled reaction mixture a blueprecipitate was filtered off and the yellow solution was concentratedunder reduced pressure and dried at high vacuum to yield a crude liquidwhich was used in (b).

(b) N,N′-bis-(2-hydroxy-5-tert.-butyl-phenyl)-terephtalamide: To 12.4 gof 2-amino-4 tert.-butylphenol (Aldrich Co.) in 50 ml of1-methyl-pyrrolidone under nitrogen atmosphere there was added 7.26 g ofterephtalic acid chloride as obtained in (a), followed by 6.1 ml ofpyridine. The mixture was heated to 80° C. for 19 hours and the reactiontraced by TLC (methylene chloride: methanol=12:1). Then the reactionmixture was cooled to 20° C., poured on a mixture of methanol/water=1:1,and filtered. The residue was washed three times with water and dried at80° C. for three days and at high vacuum at 150° C. for five hours. 16.1g (97%) of crude crystals were obtained (m.p. >250° C.).

(c) N,N′-Bis-(2-allyloxy-5-tert.-butyl-phenyl)-terephtalamide: To 10 gof the above N,N′-bis-terephtalamide in 138 ml of 1-methyl-pyrrolidone,11.4 g of anhydrous sodium carbonate and a trace of potassium iodide,4.2 ml of allylbromide was slowly added by means of a syringe undernitrogen atmosphere. A solid material was formed in the dark, reddishsolution. The mixture was heated to 70° C. for 18 hours and the reactionwas traced by TLC (ethyl acetate: bexane=1:1). Then the reaction mixturewas cooled to 10° C. A precipitate was formed, which was filtered off,washed with water and dried at 80° C. for four days in a vacuum. 10.5 g(84%) of crude crystals were obtained (m.p. 172–173° C.), which wereidentified by UV: 311 nm (E=332, in CH₂Cl₂), NMR and MS: 540(M⁺), 499,441, 336 (100%).

(d) 1,4-Bis-[2-(5-tert.-butyl-7-allyl-benzoxazol)-yl]-benzene: 10 g ofthe allyl ether as obtained in step (c) was heated in a Kugelrohrapparatus for 15 hours at 200° C.: The reaction was followed by TLC(ethyl acetate: hexane=1:1). There were obtained 9.3 g (100%) of browncrystals (m.p. 163–165° C.), which were identified by NMR and MS:504(M⁺), 489 (100%), 433, 237.

This product was 1.1% soluble in Cétiol LC (Cocoyl cyprylate caprate).It was irradiated in high dilution with a Hg-lamp 150 W (Heraeus) andshown to be photostable.

EXAMPLE 2 Preparation of1,4-bis-[2-(5-tert.-butyl-7-{3-(1,1,3,3,3-pentamethyl-disiloxanyl)-1-propyl}-benzoxazol)-yl]-benzene

To 1.6 g of the bis-(allyl-benzoxazole)-benzene obtained in Example 1 in45 ml of toluene 1.5 g of pentamethyldisiloxane (Fluka) were added and atrace of divinyl tetramethyl disiloxane platinum complex under strictnitrogen atmosphere. The reaction mixture was heated to 80° C. for 18hours and then evaporated to obtain 3 g of a brown oil. Afterchromatography in hexane/ether slightly yellow crystals were formed.M.p. 89–90° C. UV(CH₂Cl₂) 350 nm (E=551); MS: 800 (M⁺), 772, 610, 147(100%).

The solubility of this product was determined for Cétiol LC (Cocoylcyprylate caprate)=18%. The product was irradiated in high dilution witha Hg-lamp 150 W (Heraeus) and shown to be photostable.

EXAMPLE 3 Preparation of1,4-bis-[2-(7-{3-(1,1,3,3,3-pentamethyl-disiloxanyl)-1-isobutyl}-benzoxazol)-yl]-benzene

(a) N,N′-Bis-(2-hydroxy-phenyl)-terephtalamide: To 7.9 g of2-amino-phenol (Fluka) in 60 ml of 1-methyl-pyrrolidone under nitrogenatmosphere 7.26 g of terephtalic acid chloride [see example 1(a)] wereadded, followed by 6 ml of pyridine. The mixture was heated to 80° C.overnight. The reaction was traced by TLC. (methylene chloride:methanol=12:1). Then the reaction mixture was cooled to 20° C., pouredon a mixture of methanol/-water=1:1, and filtered. The crystalline,yellow residue was washed three times with water and dried at 80° C. athigh vacuum. There were obtained 10.7 g (89%) of crude crystals(m.p. >250° C.), which were identified by NMR and used in step (b).

(b) N,N′-bis-(2-methallyloxy-phenyl)-terephtalamide: To 4 g ofN,N′-bis-terephtalamide as obtained in (a) in 40 ml of1-methyl-pyrrolidone, 6.3 g of anhydrous sodium carbonate and a trace ofpotassium iodide, 2.8 ml of methallylchloride was slowly added by meansof a syringe under nitrogen atmosphere. The mixture was heated to 80° C.overnight and the reaction was traced by TLC. (ethyl acetate:hexane=1:1). Then the reaction mixture was cooled to 10° C. and waterwas added. A precipitate was formed, which was filtered off, washed withwater and dried. 4.8 g (80%) of a pale yellow solid was obtained, whichwas identified by HPLC and NMR (CDCl₃): 1.87 ppm (S/6Pr); 4.56 (S/4Pr);5.06 (S/2Pr); 5.12 (S/2Pr); 6.94 (D×D/2Pr); 7.04 (M/4Pr); 8.00 (S/4Pr):8.54 (D×D/2Pr); 8.69 (S/2Pr, NH).

(c) 1,4-Bis-[2-(7-methallyl-benzimidazol)-yl]-benzene: 4 g of the allylether obtained in (b) in 50 ml of 1,2,4-trichlorobenzene was heated toreflux in a 100 ml reaction flask for 10 hours. The reaction wasfollowed by TLC. (ethyl acetate: hexane=1:3). The reaction mixture wasconcentrated and chromatographed on silicagel to yield 0.5 g ofyellowish crystals which were identified by HPLC and NMR (CDCl₃): 1.80ppm (S/6Pr); 3.70 (S/4Pr); 4.87 (S/2Pr); 4.91 (S/2Pr); 7.20 (D/2Pr);7.32 (Tr/2Pr); 7.67 (D/4Pr): 8.40 (S/2Pr); 8.69 (S/2Pr, NH).

(d)1,4′-Bis-[2-(7-{3-(1,1,3,3,3-pentamethyl-disiloxanyl)-1-isobutyl}-benzoxazol)-yl]-benzene:To 0.45 g of the bis-(methallyl-benzoxazole)-benzene obtained in (c) in10 ml of toluene 0.5 ml of pentamethyldisiloxane (Fluka) were added and0.05 ml of 20% solution of divinyl tetramethyl disiloxane platinumcomplex in toluene under strict nitrogen atmosphere. The reactionmixture was heated to 80° C. overnight and then evaporated. Afterchromatography in hexane/ether, 0.59 g (75%) of a brownish oil wasobtained, which slowly crystallized. M.p. ca. 38° C. UV(CH₂Cl₂) 344 nm(E=736); MS: 716 (M⁺), 701, 674, 147 (100%).

The solubility of this product was determined for Crodamol DA(diisopropyladipate)=5.03%. The product was irradiated in high dilutionwith a Hg-lamp 150 W (Heraeus) and shown to be photostable.

EXAMPLE 4 Preparation of1,4-bis-[2-(5-tert.-butyl-7-methallyl-benzoxazol)-yl]-benzene

(a) N,N′-bis-(2-methallyloxy-5-tert.-butyl-phenyl)-terephtalamide: To2.76 g of N,N′-bis-(2-hydroxy-5-tert.-butyl-phenyl)-terephtalamide [seeExample 1(b)], dissolved in 38 ml of 1-methyl-pyrrolidone, 3.15 g ofanhydr. sodium carbonate and a trace of potassium iodide. 1.35 ml ofmethallylchloride was slowly added by means of a syringe under nitrogenatmosphere. The mixture was heated to 70° C. for 18 hours and thereaction was traced by TLC. (methylene chloride: methanol=4:1). Then thereaction mixture was cooled to 10° C. and poured on 200 ml of water.This mixture was extracted twice with 100 ml of ethyl acetate. Theorganic phases were washed with water, 2n NaOH and brine, dried withNa₂SO₄ and concentrated. The residue was recrystallised from toluene toyield 1.45 g (42%) of beige crystals (m.p. 184–185° C.), which wereidentified by UV: 311 nm (E=291, in CH₂Cl₂), NMR and MS: 568(M⁺), 513,350 (100%).

(b) 1,4-Bis-[2-(5-tert.-butyl-7-methallyl-benzoxazol)-yl]-benzene: 1.29g of the allyl ether obtained in (a) and a trace of boric acid in 10 mlof 1,2,4-trichlorobenzene was heated to reflux in a 100 ml reactionflask for 4.5 hours. The reaction was followed by TLC. (ethyl acetate:hexane=1:3). The reaction mixture was concentrated and precipitated withhexane and chromatographed on silicagel to yield 0.62 g (51%) ofyellowish crystals (m.p. 146–149° C.) which were identified byUV(CH₂Cl₂): 349 nm (E=1015), NMR and MS: 532(M⁺, 100%), 517, 251.

EXAMPLE 5 Preparation of1,4-bis-[2-(5-tert.-butyl-7-{3-(1,3,3,3-tetramethyl-1-[(tri-methyl-silyl)-oxy]-disiloxanyl)-1-isobutyl}-benzoxazol)-yl]-benzene

A 25 ml round bottom flask equipped with a magnetic stirrer, a refluxcondenser and an oil bath under nitrogen atmosphere was charged with 0.4g of bis-(methallyl-benzoxazole)-benzene [Example 4(b)] in 10 ml oftetrahydrofuran. 0.43 ml of 1,1,1,3,5,5,5-heptamethyl-trisiloxane(Rhodia) and 0.05 ml of 20% solution of divinyl tetramethyl disiloxaneplatinum complex in toluene was added under strict nitrogen atmosphere.The reaction mixture was refluxed during 70 hours and then evaporated.After chromatography in hexane/ethylacetate, 0.81 g (42%) of brownishcrystals were obtained (m.p. 72–73° C.). UV(CH₂Cl₂) 350 nm (E=615); MS:934 (M⁺), 714, 698, 221 (100%).

The solubility of this product was determined for Cétiol LC (Cocoylcyprylate caprate)=12.3%. The product was irradiated in high dilutionwith a Hg-lamp 150 W (Heraeus) and shown to be photostable.

EXAMPLE 6 Preparation of1,4-bis-[2-(5-methyl-7-oct-3-en-2-yl-benzoxazol)-yl]-benzene

(a) N,N′-Bis-(2-hydroxy-5-methyl-phenyl)-terephtalamide: In analogy toExample 1(b) but substituting 2-amino-4-methylphenol (Fluka) for2-amino-4-tert.-butylphenol there was obtainedN,N′-bis-(2-hydroxy-5-methyl-phenyl)-terephtalamide, yellow crystalswhich were identified by NMR (DMSO): 2.24 ppm (S/6Pr); 6.80–6.89(M/4Pr); 7.5 (D/2Pr); 8.10 (S/4Pr); 9.50 (S, broad/2Pr): 9.65 (S/2Pr).Yield 96%.

(b) N,N′-bis-(2-oct-2-enyloxy-5-methyl-phenyl)-terephtalamide: To 5 g ofthe above N,N′-bis-terephtalamide in 40 ml of 1-methyl-pyrrolidone, 7 gof anhydrous sodium carbonate and 2 mg of potassium iodide 6.4 g (33.3mmol) of 1-bromo-2-octene (prepared from 1-octene-3-ol by the method ofMiginiac and Mauzé, Bull. Soc. Chim. France 2544, 2547 (1968) wereslowly added by means of a syringe. The reaction mixture was left tostir for two hours at room temperature and for 18 hours at 80° C. Thereaction was traced by TLC. (hexane: ethylacetate=1:1). Then thereaction mixture was cooled to 20° C., poured into water and theprecipitate was filtered and washed with water and dissolved in ether.Residual solid salts were removed and the organic phase was concentratedand dried at high vacuum to yield 6.44 g (81%) of a brown solid, whichwas identified by NMR (CDCl₃): 0.87 ppm (Tr/6Pr); 1.20–1.44 (M/12Pr);2.09 (D×Tr/4Pr); 2.35 (S/6Pr); 4.57 (D/4Pr); 5.69–5.74 (M/2Pr);5.82–5.88 (M/2Pr): 6.82–6.89 (M/4Pr); 8.00 (S/4Pr); 8.38 (S/2Pr); 8.65(S/2Pr).

(c) 1,4-Bis-[2-(5-methyl-7-oct-3-en-2-yl-benzoxazol)-yl]-benzene: 4.5 g(7.6 mmol) of the aboveN,N′-bis-(2-oct-2-enyloxy-5-methyl-phenyl)-terephtalamide in 40 ml ofN,N-diethylaniline was heated to reflux (230° C.). The reaction wastraced by TLC. (hexane: ethyl acetate=3:1). After 66 hours the reactionwas completed, and a solution of 2n HCl was added to the cold reactionmixture, followed by extraction with ether (3×). The combined organicphases were washed with a 10% KOH solution, and the latter was acidifiedto pH 3–4 with 5n HCl and extracted with ether. The combined etherphases were dried over sodium sulfate and concentrated to yield 2.74 g(64%) of a white solid, which contained about 90% of the product definedabove and 10% of1,4-bis-[2-(5-methyl-7-pentyl-allyl-benzoxazol)-yl]-benzene. The lattergroup was formed by a normal Claisen rearrangement in contrast of the7-(oct-3-en-2-yl) group, which was formed by an abnormal Claisenrearrangement according to Schmid et al., Helv. Chim. Acta 51:1603(1968). M.p. 118–20° C. UV(CH₂Cl₂): 349 nm (E=690); MS: 560 (M+), 477,159 (100%), 145.

The solubility of this product mixture was determined for Crodamol DA(diisopropyladipate)=1.33%. The product was irradiated in high dilutionwith a Hg-lamp 150 W (Heraeus) and shown to be photostable.

EXAMPLE 7 Preparation of 1,4-bis-[2-(5-tert.-butyl-7-(1-pentyl-allyl)-and/or -7-(oct-3-en-2-yl)benzoxazol)-yl]-benzene

(a) N,N′-Bis-(2-oct-2-enyloxy-5-tert.-butyl-phenyl)-terephtalamide: Inanalogy to Example 6(b), but substitutingN,N′-bis-(2-hydroxy-5-tert.-butyl-phenyl)-terephtalamide (Example 1b)for N,N′-bis-(2-hydroxy-5-methyl-phenyl)-terephtalamide there wasobtained, after chromatography, 53% ofN,N′-bis-(2-oct-2-enyloxy-5-tert.-butyl-phenyl)-terephtalamide, whichwas identified by MS and NMR (CDCl₃): 0.874 ppm (Tr/6Pr); 1.2–1.36(M/30Pr); 2.08 (M/4Pr); 4.58 (D/4Pr); 5.7 (Tr×D/2Pr); 5.88 (Tr×D/2Pr);6.87 (D/2Pr); 7.08 (D/2Pr); 8.01 (S/4Pr) and 8.65 (S, broad/4Pr).

(b) 1,4-bis-[2-(5-tert.-butyl-7-(1-pentyl-allyl)- and/or-7-(oct-3-en-2-yl)benzoxazol)-yl]-benzene: 1.6 g (2.3 mmol) of the aboveN,N′-bis-(2-oct-2-enyloxy-5-tert.-butyl-phenyl)-terephtalamide in 15 mlof 1,2,4-trichlorobenzene was heated to reflux (210° C.) under nitrogenatmosphere over night. The reaction was traced by TLC. (hexane: ethylacetate=3:1). The solvent was evaporated at the Kugelrohr apparatus. 1.4g (92%) of a dark liquid was obtained, which after chromatographyyielded 0.8 g (52%) of the bis-[2-benzoxazol-yl]-benzene product,comprising an isomer carrying the 7-(pentyl-allyl) group in a proportionof about 58% and an isomer carrying the 7-(oct-2-en-1-yl) group in aproportion of about 42%, tentatively referred to herein as1,4-bis-[2-(5-tert.-butyl-7-(1-pentyl-allyl)(and/or-7-oct-3-en-2-yl)-benzoxazol)-yl]-benzene. UV(CH₂Cl₂) 349 nm (E=715);MS: 544 (M⁺′100%), 629, 534, 517.

The product was easily mixable with conventional cosmetic solvents. Thisproduct was irradiated in high dilution with a Hg-lamp 150 W (Heraeus)and was shown to be photostable.

EXAMPLE 8 Preparation of1,4-bis-[2-(5-tert.-butyl-7-oct-3-en-2-yl-benzoxazol)-yl]-benzene

In analogy to Example 6(c), but substitutingN,N′-bis-(2-oct-2-enyloxy-5-tert.-butyl-phenyl)-terephtalamide [Example7(a)] for N,N′-bis-(2-oct-2-enyloxy-5-methyl-phenyl)-terephtalamidethere was obtained, after heating for three nights to 230° C. andchromatography, a liquid product in 85% yield, which was identified tobe mainly the product defined above, formed by an abnormal Claisenrearrangement. UV(CH₂Cl₂) 350 nm (E=804); MS: 644 (M⁺), 629, 587, 561,55 (100%).

The product was easily mixable with conventional cosmetic solvents. Thisproduct was irradiated in high dilution with a Hg-lamp 150 W (Heraeus)and was shown to be photostable.

EXAMPLE 9 Preparation of1,4-bis-[2-(7-oct-3-en-2-yl-benzoxazol)-yl]-benzene

(a) N,N′-Bis-(2-oct-2-enyloxy-phenyl)-terephtalamide: In analogy toExample 6(b) but substituting N,N′-bis-(2-hydroxy-phenyl)-terephtalamide[Example 2(b)] for N,N′-bis-(2-hydroxy-5-methyl-phenyl)-terephtalamidethere were obtained, after chromatography, 69.5% of yellow crystalswhich were identified by NMR (CDCl₃): 0.87 ppm (Tr/6Pr); 1.27–1.43(M/12Pr); 2.1 (Tr×D/4Pr); 4.6 (D/4Pr); 5.72 (Tr×D/2Pr); 5.87 (Tr×D/2Pr);6.94 (D/2Pr); 7.0–7.1 (M/4Pr); 8.01 (S/4Pr); 8.54 (D/2Pr) and 8.67 (S,broad/2Pr).

(b) 1,4-Bis-[2-(7-oct-3-en-2-yl-benzoxazol)-yl]-benzene: In analogy toExample 6(c) but substitutingN,N′-bis-(2-oct-2-enyloxy-phenyl)-terephtalamide [Example 9(a)] forN,N′-bis-(2-oct-2-enyloxy-5-methyl-phenyl)-terephtalamide there wasobtained, after recrystallisation from ethanol, a pale yellowish powder(m.p. 87–89° C.) in 51% yield, which was identified to be mainly theproduct defined above, formed by an abnormal Claisen rearrangement).UV(CH₂Cl₂) 344 nm (E=1085); MS: 532 (M⁺), 629, 517, 475, 449, 145(100%).

The solubility of this product was determined for Cétiol LC (Cocoylcyprylate caprate)=1.02%. The product was irradiated in high dilutionwith a Hg-lamp 150 W (Heraeus) and was shown to be photostable.

EXAMPLE 10 Preparation of 1,4-bis-[2-(4-(or5-)tert.-pentyl-7-(1-pentyl-allyl)(and/or-7-oct-3-en-2-yl)-benzoxazol)-yl]-benzene

(a) 4- and 5-tert.-pentyl-2-aminophenol: A mixture of 1 g of2-amino-phenol (Fluka) dissolved in 20 ml of methanesulfonic acid and1.4 ml of 2-chloro-2-methylbutane was heated to 70° C. for four hours.The reaction mixture was poured on diluted NaOH with ice and extractedthree times with ether. The dried and concentrated organic phases werechromatographed to yield 0.8 g (49%) of a mixture of 4-(27%) and 5-(73%)tert.-pentyl-2-aminophenol. MS: 179 (M⁺), 150 (100%).

(b) N,N′-bis-(2-hydroxy-4-(27% share) and 5-(73% share)tert.-pentyl-phenyl)-terephtalamide: In analogy to Example 1(b) butsubstituting the above 4-(and 5-)tert.-pentyl-2-aminophenol for2-amino-4-tert.-butylphenol there were obtained yellow crystals in 92%yield, which were identified by NMR (DMSO): 0.66 ppm (Tr/6Pr); 1.22 and1.27 (2×S/12Pr); 1.59 (Q/4Pr); 6.87 (D/2Pr); 7.03 and 7.10 (2×D/2Pr);7.61 and 7.66 (2×S/2Pr); 8.11 (S/4Pr); 9.44 (S/2Pr); 9.75 (S/2Pr).

(c) N,N′-Bis-(2-oct-2-enyloxy-4-(and5-)tert.-pentyl-phenyl)-terephtalamide: In analogy to Example 6(b), butsubstituting the above N,N′-bis-(2-hydroxy-4-(27% share) and 5-(73%share)tert.-pentyl-phenyl)-terephtalamide forN,N′-bis-(2-hydroxy-5-methyl-phenyl)-terephtalamide there was obtainedthe above product which was identified by MS: 709 (M⁺), 598, 488, 310(100%).

d)1,4-Bis-[2-(4-resp.5-tert.-pentyl-7-oct-3-en-2-yl-benzoxazol)-yl]-benzene:In analogy to Example 6(c) but substituting the aboveN,N′-bis-(2-oct-2-enyloxy-4-(and 5)tert.-pentyl-phenyl)-terephtalamidefor N,N′-bis-(2-oct-2-enyloxy-5-methyl-phenyl)-terephtalamide there wasobtained after chromatography a liquid mixture of isomeric products,tentatively referred to herein as 1,4-bis-[2-(4-(or5-)tert.-pentyl-7-(1-pentyl-allyl)(and/or-7-oct-3-en-2-yl)-benzoxazol)-yl]-benzene which were identified by NMR,UV(EtOH): 350 nm (E=736), 368 nm (E=474) and MS: 673 (M⁺), 643 (100%),307.

The product was easily mixable with conventional cosmetic solvents. Thisproduct was irradiated in high dilution with a Hg-lamp 150 W (Heraeus)and was shown to be photostable.

EXAMPLE 11 Preparation of1,4-bis-[2-(5-tert.-butyl-7-oct-2-yl-benzoxazol)-yl]-benzene

A 50 ml three necked reaction flask equipped with an effective stirrerand low pressure hydrogen access was charged with 0.5 g1,4-bis-[2-(5-tert.-butyl-7-oct-3-en-2-yl-benzoxazol)-yl]-benzene (seeExample 8) and a trace of Pd 5% on carbon catalyst (Fluka) in 20 ml ofhexane. The mixture was hydrogenated for 4 hours under hydrogenatmosphere. Then the reaction mixture was filtered and concentrated toyield quantitatively a liquid. UV(EtOH) 350 nm (E=804), 368 nm (E=518).

The product was easily mixable with conventional cosmetic solvents. Thisproduct was irradiated in high dilution with a Hg-lamp 150 W (Heraeus)and was shown to be photostable.

EXAMPLE 12 Further Compounds of Formula I that can be Obtained inAccordance with the Preceeding Examples are

-   1,4-bis-[2-(5-methyl-7-oct-2-yl-benzoxazol)-yl]-benzene;-   1,4-bis-[2-(4-tert.-butyl-7-oct-2-yl-benzoxazol)-yl]-benzene;-   1,4-bis-[2-(5-tert.-.butyl-7-oct-2-yl)-benzoxazol)-yl]-benzene;-   1,4-bis-[2-(4-resp.5-tert.-pentyl-7-oct-2-yl-benzoxazol)-yl]-benzene;-   1,4-bis-[2-(5-tert.-butyl-7-hex-2-yl-benzoxazol)-yl]-benzene; and-   1,4-bis-[2-(5-tert.-butyl-7-pent-2-yl-benzoxazol)-yl]-benzene.

EXAMPLE 13 Preparation of a O/W Sunscreen Lotion UV-B and UV-A

Broad spectrum sunscreen lotion containing 1.5% of a compound of formulaI. Recipe [%] compound chemical name Part A  4 PARSOL MCX octylmethoxycinnamate  1.5 compound of formula I  1.5 PARSOL 17894-t-butyl-4′-methoxy-dibenzoyl-methane 12 Cétiol LCcoco-caprylate/caprate  4 Dermol 185 Isostearyl neopentanoate  0.25diethyleneglycol PEG-2-stearate monostearate  1 CetylalcoholCetylalcohol  0.25 MPOB/PPOB Methyl-propylparabene  0.1 EDTA BDEDTA-sodium salt  1 Amphisol Diethanolamine cetylphosphate DEA (Giv.)Part B 20 Permulene Acrylate C10–C30 alkylacrylate TR-1 (+ %) 48.6 waterdeion. water deion.  5 Propyleneglycol 1,2-propanediol  0.8 KOH (10%)potassium hydroxyde Part A is heated in a reactor to 85° C. Part B isslowly added within 10 min, followed by addition of KOH, cooling anddegassing of the emulsion.

EXAMPLE 14

Preparation of a O/W Anionic Sunscreen Lotion UV-B and UV-A

Broad spectrum sunscreen lotion containing 3% of a compound of formulaI. Recipe [%] compound chemical name Part A  5 PARSOL MCX octylmethoxycinnamate  3 product of formula I  4 PARSOL 5004-methylbenzylidene camphor  2 PARSOL 17894-t-butyl-4′-methoxy-dibenzoyl-methane  2 Glyceryl glyceryl stearatemonostearate  2 Cetyl alcohol cetyl alcohol extra  2 Ganex V-220PVP/eicosene copolymer  4 Ceraphyl 375 isostearyl neopentanoate  4Ceraphyl 847 octyldodecyl stearoyl stearate  2 Amphisol K potassiumcetylphosphate (Giv.)  0.1 Edeta BD disodium EDTA  0.6 Phenonipphenoxyethanol & methyl-, ethyl-, propyl- & butyl-paraben Part B 11.15water deion. water deion. 50 Carbopol 934 Carbomer 1% solution  5Propyleneglycol 1,2-propanediol  0.15 Nipagin M methylparaben  3 KOH(10%) potassium hydroxyde q.s. Perfume oil Fragrance Part A is heated ina reactor to 85° C. When homogeneous, add Part B, followed by additionof preheated KOH (75° C.), cooling and degassing of the emulsion.

1. A compound of formula III

wherein R¹ is hydrogen, C₁₋₂₀alkyl or C₂₋₂₀alkenyl; R²¹ is—C(R⁴,R⁵)C(R⁶)═C(R⁷,R⁸), wherein R⁴, R⁵, R⁶, R⁷ and R⁸ areindependently, hydrogen, C₁₋₁₀alkyl or C₂₋₁₀alkenyl, or C₂₋₁₀alkyl orC₃₋₁₀alkenyl containing at least one oxygen atom interrupting thehydrocarbon chain, and X is phenylene or naphthylene, or substitutedphenylene or naphthylene.